1. Technical Field
The present invention relates to a liquid crystal-containing composition utilized for display devices, image/information recording devices, space light modulators and the like, to a method of producing a liquid crystal-containing composition and to a liquid crystal display device.
2. Related Art
Cholesteric liquid crystal display devices have characteristics such as memory-storing ability to keep displayed image without power supply, bright display due to elimination of use of polarizing plate and capability to provide a color display without using a color filter. Therefore, they have attracted attention in recent years (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 05-080303).
In particular, the cholesteric liquid crystal includes helically aligned rod-like molecules and have the property of interferential reflection of the light having the equal wavelength to the helical pitch (also called selective reflection). Therefore, vivid color display can be attained without using a color filter by setting the helical pitch to a value corresponding to the wavelength of each of red, green and blue colors.
For example, a cholesteric liquid crystal sealed in a cell having a pair of substrates each having an electrode is known to take two orientation states: planar (P) orientation and focal conic (F) orientation. In the state of the P orientation, the helical axis is oriented in the direction almost perpendicular to the surface of the substrate, and selective reflection is observable. In the state of the F orientation, the helical axis is oriented in the direction almost parallel to the surface of the substrate, and this state permits transmission of light. The transition between these two orientation states can be achieved by applying voltage between the electrodes.
Therefore, when a photo-absorber in black or the like is arranged at the backside of the above cell, bright display in the selective reflection color can be achieved when the liquid crystal is in the P orientation state, and dark display in black, the color of the photo-absorber, can be achieved when the liquid crystal is in the F orientation state. The P orientation and F orientation among the above orientations can both be maintained stably without power source. Utilization of this nature makes it possible to realize a memory display that retains display without power source.